Morphological study of fruits, seeds and embryo in the tropical tribe Dipterygeae (Leguminosae-Papilionoideae)

摘要

This work analyses and describes fruit, seed and embryo morphology of 12 Dipterygeae species. The fruit is quite distinct among genera, being a legume in Taralea, a drupoid legume in Dipteryx and a cryptosamara in Pterodon. It was observed that the three genera present distinct morphological characteristics in the epicarp, mesocarp and endocarp. These structures are strongly associated with the dispersal syndromes presented by the genera. Embryonic descriptions are provided for the first time in this manuscript for the three genera presented here and the main diagnostic characteristics are: (1) a gradual extent of development of the hypocotyl-radicle axis from Taralea (undeveloped) to Dipteryx (the most developed); (2) the plumules are entire in Taralea and pinnate in Dipteryx and Pterodon; (3) a cleft below the hypocotyl-radicle axis in Taralea, absent in the other genera, because of the strongly cordate base of the cotyledonar leaves; (4) differences in the degree of development of the hypocotyl-radicle axis between D.alata, D.rosea and D.micrantha. Dipterygeae presents a noticeable diversity of fruit, seed and embryo, Taralea being the most distinct of all. The results of this morphological analysis suggest an evolutive path for the diaspores in the clade, based on phylogenetic studies which show Taralea as sister to the clade constituted by Dipteryx and Pterodon.